DNA metabarcoding provides insights into the diverse diet of a dominant suspension feeder, the giant plumose anemone Metridium farcimen

Benthic suspension feeders have significant impacts on plankton communities by depleting plankton or modifying composition of the plankton through prey selectivity. Quantifying diets of planktivorous animals can be difficult because plankton are frequently microscopic, may lack diagnostic characters, and are digested at variable rates. With DNA metabarcoding, the identification of gut contents has become faster and more accurate, and the technique allows for higher taxonomic resolution while also identifying rare and highly degraded items that would otherwise not be detected. We used DNA metabarcoding to examine the diet of the giant plumose anemone Metridium farcimen, a large, abundant, competitively-dominant anemone on subtidal rock surfaces and floating docks in the northeast Pacific Ocean. Gut contents of 12 individuals were compared to 80- and 330-micron filtered plankton samples collected one hour prior between 0.02 and 1.5 km from the anemones. The objectives of this study were to determine if M. farcimen has a selective diet and compare our findings with traditional gut content analyses.