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 on or near the islet. Cold-water coral biogenic reefs have been identified on the wider Rockall Bank, which are contributing features for the East Rockall Bank and North-West Rockall Bank SACs. In December 2013 surveys by Marine Scotland discovered four new species of animals in the sea around Rockall. These are believed to live in an area where hydrocarbons are released from the sea bed, known as a cold seep. The discovery has raised the issue of restricting some forms of fishery to protect the sea bed. The species are: The earliest recorded date of landing on the island is