Anacapa is an eDNA toolkit that allows users to build comprehensive reference databases and assign taxonomy to raw multilocus metabarcode sequence data. It address longstanding needs of the eDNA for modular informatics tools, comprehensive and customizable reference databases, flexibility across high-throughput sequencing platforms, fast multilocus metabarcode processing, and accurate taxonomic assignment. Anacapa toolkit processes eDNA reads and assigns taxonomy using existing software or modifications to existing software. This modular toolkit is designed to analyze multiple samples and metabarcodes simultaneously from any Ilumina sequencing platform. A significant advantage of the Anacapa toolkit is that it does not require that paired reads overlap, or that both reads in a pair pass QC. Taxonomy results are generated for all read types and the user can decide which read types they wish to retain for downstream analysis.
Environmental DNA (eDNA) metabarcoding is becoming a core tool in ecology and conservation biology, and is being used in a growing number of education, biodiversity monitoring, and public outreach programs in which professional research scientists engage community partners in primary research. Results from eDNA analyses can engage and educate natural resource managers, students, community scientists, and naturalists, but without significant training in bioinformatics, it can be difficult for this diverse audience to interact with eDNA results. Here we present the R package ranacapa, at the core of which is a Shiny web app that helps perform exploratory biodiversity analyses and visualizations of eDNA results. The app requires a taxonomy-by-sample matrix and a simple metadata file with descriptive information about each sample. The app enables users to explore the data with interactive figures and presents results from simple community ecology analyses. We demonstrate the value of ranacapa to two groups of community partners engaging with eDNA metabarcoding results.
DNA metabarcoding is an important tool for molecular ecology. However, metabarcoding effectiveness hinges on the quality of reference databases for taxa and loci of interest. This limitation is true for metabarcoding of marine fishes in the California Current ecosystem where there is a paucity of reference 12S barcodes. Here we present FishCARD, a California Current-specific marine fish 12S-specific reference barcode database. We barcoded 612 species using the MiFish metabarcoding primers; an addition of 258 species to the 459 California Current fish species with existing 12S barcodes from GenBank. The resulting FishCARD database covers 82.7% of California Current marine fishes, and it includes virtually all fishes sampled by large marine monitoring programs such as the Partnership for Interdisciplinary Studies of Coastal Oceans and California Cooperative Oceanic Fisheries Investigation. To demonstrate the importance of complete reference databases for eDNA metabarcoding, we compared species and reads identified from three 1L seawater samples collected off Santa Cruz Island, CA using GenBank sequences with and without our generated barcodes, as well as the FishCARD database curated here. The inclusion of our generated barcodes allowed for the additional identification of 15 native taxa and 21.8% of total reads from eDNA samples. However, we found that half of all amplicon sequence variants (ASVs) generated by MiFish 12S primers were of non-vertebrate 16S origin, demonstrating a clear limitation of a widely employed fish metabarcoding primers. Despite these limitations, FishCARD provides an important genetic resource to enhance the effectiveness of marine metabarcoding efforts in the California Current ecosystem.