The scientific name "hydrobates" derives from Greek "", from "hydōr" "water", and "batēs" "walker", and "pelagicus" from "pelagikos" "pelagic, of the (open) sea", from "pelagos" "sea, open sea, high sea". There are two recognised subspecies, the North Atlantic nominate subspecies, "H. p. pelagicus" (Linnaeus, 1758), and the Mediterranean "H. p. melitensis" (Schembri, 1843). Although there is some genetic support for classifying the southern form as a separate species, the morphology is not considered sufficiently different from that of the nominate subspecies to justify a split.