Black dogfish to the clade formed by the granular dogfish ("C. granulatum") and combtooth dogfish ("C. nigrum"). The black dogfish is a common species, with a wide but discontinuous distribution in the temperate waters of the Atlantic Ocean; its range abuts, but does not extend into, the Arctic Ocean. In the northeast, it occurs from Iceland to Sierra Leone, including the Faroe Islands, southern Norway, and the Rockall Trough and Porcupine Seabight off Ireland. In the northwest, it is found from southern Greenland and Baffin Island to Virginia, being particularly abundant in the Laurentian Channel, and may occur further south to the
Rockall Natural Resources, to conduct a seismic survey of the Rockall Bank and the Hatton Bank in July 2004, as part of the Irish National Seabed Survey. The island's only permanent macro-organism inhabitants are common periwinkles and other marine molluscs. Small numbers of seabirds, mainly fulmars, northern gannets, black-legged kittiwakes, and common guillemots, use the rock for resting in summer, and gannets and guillemots occasionally breed successfully if the summer is calm with no storm waves washing over the rock. In total there have been just over twenty species of seabird and six other animal species observed (including the aforementioned molluscs)