A new species of Ophryotrocha was discovered on whalebones in Greenland (120 m depth) and at finfish aquaculture sites in Newfoundland (30–70 m depth), where it is considered to be a bioindicator of aquaculture-related organic enrichment. Phylogenetic analyses based on three genes (COI, 16S mitochondrial and H3 nuclear genes) show close affinities with O. lobifera and O. craigsmithi, two species also found on both whalebones and at aquaculture sites (North Sea), and with O. shieldsi from aquaculture sites in Tasmania. The new species is named Ophryotrocha cyclops sp. nov. due to the juxtaposed, quasi-fused central eyes that give the impression of a single eye in live specimens.