eDNA Metabarcoding
To test the utility of the FishCARD database, we metabarcoded fish eDNA from 3 sites off Eastern Santa Cruz Island, CA in 2017. We collected seawater samples from 10m depth using a 4 L Niskin bottle. From this sample, we gravity filtered 1 L through a 0.2 µm Sterivex (Millipore Sigma, Burlington, MA, USA) filter in the field and preserved on ice before being transported to a -20˚C freezer. We then extracted eDNA from the filters using the modified Qiagen DNeasy Blood and Tissue Kit extraction protocol of Spens et al. (2017), and then amplified it via PCR using the MiFish Teleost primers and thermocycler profile above. We prepared libraries following the methods of Curd et al. (2019) and sequenced these samples on an Illumina MiSeq PE 2x300 at UCLA Technology Center for Genomics and Bioinformatics (see Supplemental Methods for detailed library preparation protocol).